In recent years, the nanotechnology has been highlighted and the carbon nanotube has attracted the attention of various fields. Development of practical application to probes, micromachines, conductive materials, thermal conductive materials, fuel batteries and solar batteries or many interesting uses for hydrogen storage materials has been actively-studied by taking advantage of specific functions of the carbon nanotubes. Conventionally, formed articles of carbon materials are accomplished by using resins, rubbers, thermoplastic elastomers, adhesives, paints, inks, metals, alloys, ceramics, cements, gelled materials, paper, fabrics, nonwoven fabrics and the like as a matrix. The matrix has been selected depending on required performances such as hardness, mechanical strength, heat resistance, electric properties, durability and reliability of an objective complex formed article. Publications for forming the complex using the carbon nanotubes include the following references, and the technologies to combine the carbon nanotube in place of conventional carbon black and carbon fibers with the resin are disclosed.
Patent Document 1: JP 2002-273741-A Publication
Patent Document 2: JP 2003-221510-A Publication
Patent Document 3: JP 2003-12939-A Publication
Patent Document 4: JP 2002-265209-A Publication
In Patent Document 1, a carbon nanotube complex formed article formed in a state in which the carbon nanotubes are arranged in a constant direction in the matrix has been described. At least one organic polymer selected from thermoplastic resins, curable resins, rubbers and thermoplastic elastomers is used as the matrix.
In Patent Document 2, a thermoplastic resin composition composed of (A) 20 to 99.95% by mass of a thermoplastic resin and (B) 0.05 to 20% by mass of carbon nanotubes comprising (C) 0.05 to 30 parts by mass of a flame retardant and 0 to 2 parts by mass of a polyfluoroolefin resin relative to 100 parts by mass of a total amount of (A) and (B) is disclosed as a conductive thermoplastic resin composition wherein an appearance of a molded article is good, mechanical strength is enhanced and flame resistance is high.
In Patent Document 3, a carbon-containing resin composition wherein components [A] substantially do not form an aggregate one another and are uniformly dispersed in components [B] without interlacing and the component [A] is in the range of 0.01 to 1.8% by weight and the component [C] is in the range of 0.1 to 55% by weight relative to 100% by weight of the composition is disclosed as the carbon-containing resin composition having excellent dynamic property and moldability and if necessary combining with excellent conductivity.
Component [A]: Carbon nanotubes with an average diameter of 1 to 45 nm and an average aspect ratio of 5 or more
Component [B]: Resin
Component [C]: Filler
These prior arts all relate to enhancing electric, thermal or mechanical nature by adding the carbon nanotube to the matrix. The addition of the carbon nanotube adamantly aims at enhancing the physical property of the matrix, and does not enable to use the excellent physical property of the carbon nanotube in a macro state. The present inventors have thought up that it is the most desirable to construct an aggregate composed of the pure carbon nanotubes alone in order to maximally leverage the physical property of the carbon nanotube. Thus, it has been made a problem to obtain the aggregate of the carbon nanotubes, which was not carried out in the above prior publications.